Clutch



May 21, 1946. J. J. BLOOMFIELD 2,400,525

I CLUTCH I I Original Filed July 7 1941 Inventor v John J.B|oomf'ield W Patented May 21', 1946 CLUTCH John J. Bloomfield, Burbank, Calif., assignor, by

mesne assignments, to Lockheed Aircraft Corporation, a corporation of California Original application July 7, 1941, Serial No.-

401,328. Divided and this application September 13, 1943, Serial No. 502,088

' 3 Claims.

This invention relates to clutches for the transmission of'po'wer, and relates more particularly to one-way or overrunning clutch mechanisms embodying means for locking up the one-way drive device. A general object of this invention is to provide a practical, dependable and highly effective clutch mechanism of this character.

.This application is a division of application Serial Number 401,328, filed July 7, 1941, entitled, 1

In such a structure it is desirable to lock up the one-way clutch to transmit torque from the driven element, or propeller, to the engin or engines. It is to be understood that the invention is capable of embodiment in mechanisms suitable for other installations and the reference herein to its embodiment in aircraft is not to be construed as limiting either the scope or application of the invention. Another object of the invention is to provide a clutch mechanism of the character referred'to embodying a mechanical one-way or overrunning clutch for the normal transmission of power from the driver to the driven element, and a magnetically actuated clutch for locking up the mechanism for the transmission of power from the normally driven element to the driver or engine.

. Another object of the invention is to provide a clutch mechanism of the character referred to in which the magnetic clutch or lock-up means is capable of operating under heavy loads and speed differentials. The magnetically operated clutch means provides for the direct frictional contact of the clutch elements for thetransmission of torque and is operable to maintain these elements in firm engagement for the transmission of heavy torque. The magnetic clutch means embodied in the mechanism does not depend upon the resistance to disturbance ,oiiered by a ma netic field or flux for thetransmission of the power, but provides for the transmission of the power through directly engaged mechan cal elements.

A further object of the invention is to provide a clutch mechanism of the character referred to which is compact and relatively light in weight, the elements being related so that one clutch part of th magnetic clutch means is carried by the driven part of the mechanical .clutch.

Other objects and features of the invention will be readily understood from the following detailed description of a typical illustrative embodiment,

throughout which description reference will be made to the accompanying drawing which is a central longitudinal detailed sectlonalview of the mechanism.

In the drawing, id designates the driving element which may be considered the crank shaft of an engine. A suitableanti-friction bearing ii serves to support the outboard end of the shaft. A nut i2 is threaded on the outboard end of the shaft and is lockedthereon by a screw I3. A flange I4 on the nut it bears against the inner race ofthe bearing i i.

The overrunning clutch includes a hub l5 connected with the drive shaft ill by splines IS. The opposite ends of the hub i5 are recessed to receive ball bearings ll.

ii is retained in its groove by a plat i 8. The bushing or collar l9 which carries the bearin H engages the plate l8 so that the plate is. held against the ends of the hub l5 and the outermost bearing ll. eludes an outer'member or shell 20 surrounding the hub i5 and rotatably supported thereon by the bearings i'l. Rollers 2| are arranged between the hub i5 and the shell 20 to complete the overrunning clutch assembly. The rollers 21 wedge between the hub and the shell to transmit torque upon rotation of the shaft Iii in one direction, this o ration being typical of roller type overrunning clutches. Upon rotation of the shaft ID in the other direction, the rollers 2| ar free to permit free wheeling or overrunning of the shell 20. In the particular application of the invention illustrated, the driven element of'the mechanism is a pinion 22 formed on the periphery of the shell.

The magnetic clutch means includes a disc 23 splined on the shaft l0 ator beyond the inner end of the hub I5 and an opposing disc 24 shiftably connected with the shell 20 by splines 25. Stop pins 26 on the disc 24 are engageable with the end face of the shell 20 to limitthe releasing movement of the disc. The clutch discs 23 and 24 have extensive annular surfaces opposing one another and lying in planes normal to the longitudinal axis of the shaft to. A friction ring 21 is secured to the hub portion of the disc 23 and engages between the disc and the inner end of the hub IS. The ring 21 may be pinned to the disc 23 and serves to dampen out slight move- The outermost bearing The overrunning clutch further in- 2 ment between the disc and the hub l5. A somewhat similar ring 28 is engaged between the other side of the disc 23 and aflange 29 on the shaft.

housing 9 to serve as a torsional vibration damp- 1 er. It will be observed that the disc 24 is carried directly by the shell 2|! and that the disc 23 is carried directly by the shaft In so that frictional cooperation between the discs operates to cut out or by-pass the one-way clutch rollers,2|.

The magnetic clutch means further includes I an electro-magnetic winding 30 on one of the stantial thickness to provide a flywheel effect for the drive shaft l and the relatively thick disc is provided with a groove 3| in its inner surface for receiving a winding 30. The thick walled disc 23 provides an adequate flux path for the coil. The groove 3| is open at the active face of the disc so that the flux path may be a closed circuit completed through the disc to obtain the maxi... mumfiux pressure.

In accordance with the broader aspects of the invention any selected form of electro-magnetic winding may be employed. It is preferred, however; to emplo the type of winding described and claimed in my copending application referred to above. This preferred winding is in the nature of a preformed ring constructed of a thin aluery of the disc 23 to cooperate with the outer One or more set screws 33 are threaded through radial openings in the periph- It has a diametric'opening 44 carrying the ends of a cross tube 45. The outer ends of the cross tube 44 are open to the interior of the ported hub l-5. Spaced radial openings 46 are provided in the cross tube 44 to communicate with the interior of the tubular shaft III. A plug 41 spaced inwardly from the cross tube closes the shaft I0 against the inward flow of lubricant. Oil or other lubricant supplied to the terminal 4| passes through the outboard portion of the'shaft III to enter the cross tube 45. The oil continues outwardly through the cross tube 45 to the interior of the hub IE to lubricate the hub, the rollers 2| and the bearings I1, Lubricant openings 48 may be provided in the hub l5 to conduct the oil from the lightening openings 39 to the bearings The magnetic clutch means further includes a layer or ring 49 of compressible resilient material for providing an initial frictional cooperation between the discs 23 and 24 upon energization of the electro-magnetic coil 30 and for overcoming the residual magnetic flux upon de-ener'gization of the winding. I prefer to construct the ring 49 of cork or pressed ground cork to'be eifective as a friction element andto have sufllcient redisc 24 to oppose the groove 3| and to partially receive the resilient ring 49. The ring 49 is proportioned to be compressed to some extent when the coil 30 is energized and this compression of convolution of the coil to secure the coil in the groove and to assure an effective grounding of g the coil.

An axial opening 34 extends through the disc 23 to communicate with the groove 3|. A tubular insulator 35 lines the opening 34. A plug 36 is arranged in the insulator 35 and is cut away at its inner end to partially receive the inner portion of the coil 30; The inner convolution of the coil 30 is electrically secured to the plug 36.

A.plug 31 of dielectric material is arranged in the outboard end of the tubular shaft I0 and may be secured or locked therein by the screw I3 A lead-in wire 38 extends through an opening in the plug 31, then passesthrough an opening 38 in thetubllar shaft It to continue through the collar l9 and plate I8 to a lightening opening 39 in the hub 5, The wire 38 continues through an opening 40 in the ring 21 and Passes outwardl to the plug 36 with which it is electrically connected.

Suitable terminal means is provided for the outer end of the wire 38. I have shown a central tubular terminal 4| engaged in the plug .31 and carrying a sleeve 42. .A coiled spring 43 surrounds the sleeve 42 and is electricall connected the ring allows the active faces of the discs .23 and 24 to come into direct engagement; It is to be observed that the force utilized to compress the ring 4|] is not lost, as it is in the case of springs frequently used in clutches, but is usefully employed to maintain the ring in the torque transmitting condition between the discs 23 and 24. The opposing grooves 3| and 50 divide the active faces of the discs 23 and 24 into spaced annular surfaces. stantially toroidal path for the magnetic fiux.

In the operation of the mechanism when the shaft H! is rotating in what may be considered the forward direction, the rollers 2| bind or engage between the hub IE and the shell 20 to.

transmit the power or torque to the driven element or pinion 22. When the shaft I0 is idle and .the driven element is rotating, for example, because of windmilling of th propeller, the rollers 2| assume inactive positions and the driven element is free to rotate with respectto the shaft. In a like manner, when the shaft In is rotated in a reverse direction, the rollers 2| assume inactive positions and no torque is transmitted to the driven element. If it is desired to lock up the clutch mechanism in either of the two last named situations the electro-magnetic coil 30 is energized. Upon energization of the rotation. The magnetic clutch. meansmay be This aids in defining a subenergized to provide for the effective reverse away from the disc 23 to disengage the magnetic clutch. This action of the ring 49 overcomes the tendency of the residual magnetic flux .to cause the clutch to drag after the coil 30 has been de-energized.

Having described only a typical form or the invention, I do not wish to be limited to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

I claim:

1. A clutch ment operable to normally drive in one direction, a second element intended to be normally driven in said direction, an overrunning clutch means operable to transmit torque in said direction from the first element to the second element and adapted to allow rotation of the second element relative to the first element in said direction. and clutch means for transmittingtorque in said direction from the second element to the first element including a clutch member rotatable'with each element, one member being movable into and out of engagement with the other member,

and an electro-magnet coil on amember for moving the movable member into torque transmitting contact with said. other member, and resilient Iriction material compressed between ment operable to transmit torque from the hub mechanism comprising a first elesaid members upon said movement of the movable member and expansible to tree the members one from the other upon the de-energization of the coil.

2. In a mechanism of the character described, a drive shaft, a hub on the shaft rotatable therewith. a driven element surrounding the hub, overrunning clutch means betweenthe hub and eleto the element upon rotation of the-shaft in one direction only, a clutch member. fixed to the shaft, s second clutch member rotatable with the-element and shiftable into torque-transmitting engagement withthe first named member, and electro-magnetic means on one of the memhas for moving the second member into engagement with said first named member when it .is

desired to transmit torque from said element to the shaft in said direction of rotation.

3. In a mechanism of the character described,

with, a driven element surrounding the hub,

' overrunning' clutch means between the hub and element operable to transmit torque from the hub to the element upon rotation of the shaft in one direction only, a clutch member fixed to and an electro-magnetic coil means on the first named member for so shitting said second member when it is desired to transmitrotation be-.

tween the element and hub in said direction.

JOHN J. BLOOMFIELD; j 

